Millwall manager Neil Harris has warned his players that they risk being left out of the team for their Championship opener against Nottingham Forest.

The Lions were frustrated by an uncompromising Barnet defence as John Akinde gave them the lead at the break.

Harris’ side would respond with their own chances, but time and again were stung by the Bees’ stubborn back four.

Two changes late on to bring in James Brown and Kris Twardek were not enough to find an equaliser as they lost 1-0 in north London.

He told News Shopper: “No excuses. I thought [we came in with] a pre-season mentality, I saw it last year and the year before at times.

“Today, certainly the first 20 minutes were really poor.”

Asked whether the performance was down to its non-competitive nature, he said: “I wouldn’t say complacency is the wrong word. Today was about amassing minutes and there will be a different team that plays on Tuesday and they will be amassing minutes as well.

“You will see a much closer line-up to my starting line-up against Nottingham Forest and next Saturday against Granada.

“And unfortunately some of the players today won’t be near that.”

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Harris is actively looking to add another centre back ahead of the upcoming Championship campaign, coming in alongside defenders Byron Webster, Shaun Hutchinson and skipper Tony Craig.

But he wants players to fight for their chances.

He said: “I want competition for places and building a competitive squad, giving everyone an opportunity over the course of pre-season to prove themselves, new players and new players who have been here previously.

“But just because I bring in new players doesn’t mean that they will be in the starting 11, and players that have done well for me over the last two years certainly won’t allow their complacency to set in thinking that they are going to be in my starting 11.

“There are some tough decisions leading up to the Forest game and there are going to be some very disappointed people.”